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| author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
|---|---|---|
| committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
| commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
| tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /arch/powerpc/boot/util.S | |
| parent | Initial commit. (diff) | |
| download | linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip | |
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
| -rw-r--r-- | arch/powerpc/boot/util.S | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/arch/powerpc/boot/util.S b/arch/powerpc/boot/util.S new file mode 100644 index 000000000..6a92376da --- /dev/null +++ b/arch/powerpc/boot/util.S @@ -0,0 +1,67 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Copied from <file:arch/powerpc/kernel/misc_32.S> + * + * This file contains miscellaneous low-level functions. + * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) + * + * Largely rewritten by Cort Dougan (cort@cs.nmt.edu) + * and Paul Mackerras. + * + * kexec bits: + * Copyright (C) 2002-2003 Eric Biederman <ebiederm@xmission.com> + * GameCube/ppc32 port Copyright (C) 2004 Albert Herranz + */ +#include "ppc_asm.h" + +#define SPRN_PVR 0x11F /* Processor Version Register */ + + .text + +/* udelay needs to know the period of the + * timebase in nanoseconds. This used to be hardcoded to be 60ns + * (period of 66MHz/4). Now a variable is used that is initialized to + * 60 for backward compatibility, but it can be overridden as necessary + * with code something like this: + * extern unsigned long timebase_period_ns; + * timebase_period_ns = 1000000000 / bd->bi_tbfreq; + */ + .data + .globl timebase_period_ns +timebase_period_ns: + .long 60 + + .text +/* + * Delay for a number of microseconds + */ + .globl udelay +udelay: + mulli r4,r3,1000 /* nanoseconds */ + /* Change r4 to be the number of ticks using: + * (nanoseconds + (timebase_period_ns - 1 )) / timebase_period_ns + * timebase_period_ns defaults to 60 (16.6MHz) */ + mflr r5 + bcl 20,31,0f +0: mflr r6 + mtlr r5 + addis r5,r6,(timebase_period_ns-0b)@ha + lwz r5,(timebase_period_ns-0b)@l(r5) + add r4,r4,r5 + addi r4,r4,-1 + divw r4,r4,r5 /* BUS ticks */ +1: MFTBU(r5) + MFTBL(r6) + MFTBU(r7) + cmpw 0,r5,r7 + bne 1b /* Get [synced] base time */ + addc r9,r6,r4 /* Compute end time */ + addze r8,r5 +2: MFTBU(r5) + cmpw 0,r5,r8 + blt 2b + bgt 3f + MFTBL(r6) + cmpw 0,r6,r9 + blt 2b +3: blr |